#include "md5.h"

#include <cassert>
#include <cstring>

using namespace std;

/******************************************************************************/

/*
	MD5C.C - RSA Data Security, Inc., MD5 message-digest algorithm

	Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All rights 
	reserved.

	License to copy and use this software is granted provided that it is 
	identified as the "RSA Data Security, Inc. MD5 Message-Digest Algorithm" in 
	all material mentioning or referencing this software or this function. 

	License is also granted to make and use derivative works provided that such 
	works are identified as "derived from the RSA Data Security, Inc. MD5 
	Message-Digest Algorithm" in all material mentioning or referencing the 
	derived work. 
	
	RSA Data Security, Inc. makes no representations concerning either the 
	merchantability of this software or the suitability of this software for 
	any particular purpose. It is provided "as is" without express or implied 
	warranty of any kind. 
	
	These notices must be retained in any copies of any part of this 
	documentation and/or software. 
*/

/******************************************************************************/

/* Constants for MD5Transform routine. */

#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

static void MD5Transform (XMP_Uns32 [4], XMP_Uns8 [64]);
static void Encode (XMP_Uns8 *, XMP_Uns32 *, XMP_Uns32);
static void Decode (XMP_Uns32 *, XMP_Uns8 *, XMP_Uns32);

static XMP_Uns8 PADDING[64] =
	{
     0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
	};

/* F, G, H and I are basic MD5 functions.

      */

#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

/* ROTATE_LEFT rotates x left n bits.

      */

#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
Rotation is separate from addition to prevent recomputation.

      */

#define FF(a, b, c, d, x, s, ac) { \
     (a) += F ((b), (c), (d)) + (x) + (XMP_Uns32)(ac); \
     (a) = ROTATE_LEFT ((a), (s)); \
     (a) += (b); \
     }
#define GG(a, b, c, d, x, s, ac) { \
     (a) += G ((b), (c), (d)) + (x) + (XMP_Uns32)(ac); \
     (a) = ROTATE_LEFT ((a), (s)); \
     (a) += (b); \
     }
#define HH(a, b, c, d, x, s, ac) { \
     (a) += H ((b), (c), (d)) + (x) + (XMP_Uns32)(ac); \
     (a) = ROTATE_LEFT ((a), (s)); \
     (a) += (b); \
     }
#define II(a, b, c, d, x, s, ac) { \
     (a) += I ((b), (c), (d)) + (x) + (XMP_Uns32)(ac); \
     (a) = ROTATE_LEFT ((a), (s)); \
     (a) += (b); \
     }

/* MD5 initialization. Begins an MD5 operation, writing a new context.

      */

void MD5Init (MD5_CTX * context)
{
     context->count[0] = context->count[1] = 0;

       /* Load magic initialization constants.

*/
     context->state[0] = 0x67452301;
     context->state[1] = 0xefcdab89;
     context->state[2] = 0x98badcfe;
     context->state[3] = 0x10325476;
}

/* MD5 block update operation. Continues an MD5 message-digest
     operation, processing another message block, and updating the context.

      */

void MD5Update (	MD5_CTX *context, /* context */
					XMP_Uns8 *input, /* input block */
					XMP_Uns32 inputLen) /* length of input block */
{
	using namespace std;

     XMP_Uns32 i, index, partLen;

       /* Compute number of bytes mod 64 */
       index = (XMP_Uns32)((context->count[0] >> 3) & 0x3F);

       /* Update number of bits */
       if ((context->count[0] += ((XMP_Uns32)inputLen << 3))
        < ((XMP_Uns32)inputLen << 3))
      context->count[1]++;
       context->count[1] += ((XMP_Uns32)inputLen >> 29);

     partLen = 64 - index;

       /* Transform as many times as possible.

*/
     if (inputLen >= partLen) {
	 std::memcpy (&context->buffer[index], input, partLen);	// AUDIT: From public MD5 code, assumed safe.
     MD5Transform (context->state, context->buffer);

     for (i = partLen; i + 63 < inputLen; i += 64)
     MD5Transform (context->state, &input[i]);

     index = 0;
     }
     else
     i = 0;

       /* Buffer remaining input */
	 std::memcpy (&context->buffer[index], &input[i], inputLen-i);	// AUDIT: From public MD5 code, assumed safe.

}

/* MD5 finalization. Ends an MD5 message-digest operation, writing the
     the message digest and zeroizing the context.

      */

void MD5Final (	XMP_Uns8 digest[16], /* message digest */
				MD5_CTX *context /* context */)
{
     XMP_Uns8 bits[8];
     XMP_Uns32 index, padLen;

       /* Save number of bits */
       Encode (bits, context->count, 8);

       /* Pad out to 56 mod 64.

*/
     index = (XMP_Uns32)((context->count[0] >> 3) & 0x3f);
     padLen = (index < 56) ? (56 - index) : (120 - index);
     MD5Update (context, PADDING, padLen);

       /* Append length (before padding) */
       MD5Update (context, bits, 8);
       /* Store state in digest */
       Encode (digest, context->state, 16);

       /* Zeroize sensitive information.

*/
	assert ( sizeof(*context) == sizeof(MD5_CTX) );
    memset ( context, 0, sizeof (*context) );	// AUDIT: Safe, using sizeof destination.
}

/* MD5 basic transformation. Transforms state based on block.

      */

static void MD5Transform (	XMP_Uns32 state[4],
							XMP_Uns8 block[64])
{
     XMP_Uns32 a = state[0], b = state[1], c = state[2], d = state[3], x[16];

     Decode (x, block, 64);

       /* Round 1 */
       FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
       FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
       FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
       FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
       FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
       FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
       FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
       FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
       FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
       FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
       FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
       FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
       FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
       FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
       FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
       FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

      /* Round 2 */
       GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
       GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
       GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
       GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
       GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
       GG (d, a, b, c, x[10], S22,  0x2441453); /* 22 */
       GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
       GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
       GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
       GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
       GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
     GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
     GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
     GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
     GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
     GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

       /* Round 3 */
       HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
       HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
       HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
       HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
       HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
       HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
       HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
       HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
       HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
       HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
       HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
       HH (b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
       HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
       HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
       HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
       HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */

       /* Round 4 */
       II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
       II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
       II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
       II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
       II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
       II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
       II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
       II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
       II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
       II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
       II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
       II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
       II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
       II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
       II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
       II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */

     state[0] += a;
     state[1] += b;
     state[2] += c;
     state[3] += d;

       /* Zeroize sensitive information.
*/
    memset (x, 0, sizeof (x));
}

/* Encodes input (XMP_Uns32) into output (XMP_Uns8). Assumes len is
     a multiple of 4.

      */

static void Encode (	XMP_Uns8 *output,
						XMP_Uns32 *input,
						XMP_Uns32 len)
{
     XMP_Uns32 i, j;

     for (i = 0, j = 0; j < len; i++, j += 4) {
     output[j] = (XMP_Uns8)(input[i] & 0xff);
     output[j+1] = (XMP_Uns8)((input[i] >> 8) & 0xff);
     output[j+2] = (XMP_Uns8)((input[i] >> 16) & 0xff);
     output[j+3] = (XMP_Uns8)((input[i] >> 24) & 0xff);
     }
}

/* Decodes input (XMP_Uns8) into output (XMP_Uns32). Assumes len is
     a multiple of 4.

      */

static void Decode (	XMP_Uns32 *output,
						XMP_Uns8 *input,
						XMP_Uns32 len)
{
     XMP_Uns32 i, j;

     for (i = 0, j = 0; j < len; i++, j += 4)
     output[i] = ((XMP_Uns32)input[j]) | (((XMP_Uns32)input[j+1]) << 8) |
     (((XMP_Uns32)input[j+2]) << 16) | (((XMP_Uns32)input[j+3]) << 24);
}
